If they had given it to specific companies before it was finished the benchmarks would not represent reality while it was under development, and as part of the embargo on these beta clients, they wouldn't be allowed to publish it.

Obviously not good if it makes it into the public release.

Because people are irrational and clickbait runs rampant.

If they contract testing of the beta to a 3rd party, they don't want them running benchmarks because if they get released, news organizations will jump on it, broadcasting the performance hit.

This matters because when later beta versions improve performance, the news about the improved performance doesn't spread nearly as much. Even if it does, the first impression sticks, and there's nothing Intel will be able to do about it.

Amazing how many people are still doing mental gymnastics to give Intel the benefit of the doubt. This should have stopped being the default position a while ago.

If it's a limited access beta version, restricting redistribution and benchmark publishing makes a lot more sense.